This description relates to a navigation system and a method of guiding a moving object through a drive path within the navigation system.
As the number of various moving objects, such as automotive vehicles and the like, have increased on roads and highways, traffic congestion and other stresses on infrastructure have also increased. Specifically, the number of vehicles is increasing considerably faster than the realized increase and improvements to the supporting infrastructure. Accordingly, navigations systems within vehicles and other moving objects provide a way of avoiding and/or reducing traffic congestion.
The navigation system detects a current position using navigation messages transmitted from a plurality of GPS (global positioning system) satellites and moving-object drive state detecting signals detected by a plurality of sensors provided to the corresponding moving object, such as a gyroscope, a speed sensor and the like. If a current position of the moving object is detected, the detected current position of the moving object is matched to map data. The current position of the moving object is displayed on a display unit together with a corresponding map. The navigation system provides the functionality of searching a drive path of a moving object from an origination to a destination using the map data and the functionality of guiding the drive path to enable the moving object to drive along the searched drive path.
The navigation system searches prescribed guide targets in front of the moving object, such as an intersection, an underpass, an overpass, a highway entrance/exit and the like, when the moving object is driving along the searched drive path. If the moving object approaches the searched guide target within a prescribed distance, the navigation system guides the drive path via a voice signal and the like. The navigation system determines if the moving object deviates from the searched drive path and drives along another, different path. If deviation from the drive path is determined by the navigation system, the navigation system informs a user of the deviation from the drive path to enable the user to correctly maneuver the moving object along the proper drive path. Therefore, the navigation system searches for the proper drive path of the moving object and guides the moving object along the proper drive path so that the given road system can be efficiently utilized.
The navigation system detects a current position of the moving object and determines whether a guide target is located within a set distance in front of the drive path by taking the detected current position as a reference. If the guide target is located within the set distance, the navigation system indicates a drive direction for the moving object to take from the corresponding guide target, such as indicating a left turn, using a voice signal and a drive direction icon displayed on the display unit. In guiding the drive direction of the moving object using the guide voice signal and the drive direction icon, the navigation system can accurately guide the drive direction of the moving object if the guide targets located ahead of the moving object are separated from each other by relatively large distances.
However, if the guide targets located ahead of the moving object are considerably close to each other, the typical navigation system has difficulty in determining where the guide target for guiding the drive direction is accurately located. Hence, the user may frequently deviate from the drive path by driving the moving object in the drive direction guided according to the location of an unguided target.
For instance, it is assumed that a moving object 100, as shown in FIG. 1a, sequentially drives along links between nodes 102, 104 and 106, and then turns to the right at the node 106 as an intersection to drive on the link between the node 106 and a node 108. A navigation system determines whether the node 106, as a guide target of a drive path, is located within a set distance ahead of the moving object 100. In particular, the navigation system determines whether the moving object 100 has arrived at a guide point P1 to guide the drive path for the node 106 as the guide target.
If the moving object 100 has arrived at the guide point P1, the navigation system guides a right turn at the node 106 using a voice signal. The navigation system also displays a drive direction icon for guiding the right turn, as shown in FIG. 1b, on a display unit. The user checks the drive direction icon displayed on the display unit and then turns the moving object 100 to the right at the node 106.
However, where the two nodes 104 and 106 which both support right turns in the same direction are relatively close to each other, the navigation system guides a right turn of the moving object 100 at the guide point P1 corresponding to a position behind the node 104 before the moving object 100 has arrived at the node 104 or 106. The user of the moving object 100 may be unable to correctly determine whether to make a right turn at the node 104 or at the node 106 using the guide voice signal and the drive direction icon displayed on the display unit only. Accordingly, the user of the moving object 100 fails to correctly turn the moving object 100 to the right at the node 106, but may make a right turn at the node 104 and thus deviate from the drive path.
The Korean Patent Application No. 63322 filed in 2002 (Public Laid-Open No. 2004-34009), the entire contents of which are incorporated by reference herein, describe that a bent angle of a drive direction icon is adjusted to be displayed according to an angle of each link on which a moving object drives. Therefore, a user of the moving object driving on a current link can correctly check an angle of a next link, on which the moving object is to drive after passing through an intersection, e.g., using the bent angle of the drive direction icon.